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Medium

Ash.Policy.Authorizer returns records denied by a runtime read policy to any actor

Type: advisorySources: OSV

Incorrect Authorization vulnerability in ash-project ash returns records that a runtime read policy denies to any actor. When a resource has an access_type :runtime read policy (a check evaluated per record rather than compiled to a filter), Ash.Policy.Authorizer decides each record in check_result/1 (lib/ash/policy/authorizer/authorizer.ex) by discarding impossible policy scenarios and inspecting what remains. When every scenario for a record was impossible, meaning no policy can authorize it and it must be forbidden, the empty-scenario branch instead kept the record ({[record | data], authorizer, any_forbidden?}) and returned it as authorized. As a result, records the runtime read policy denies are returned to any actor. The fix forbids a record whose scenarios are all impossible. This issue affects ash: from 3.4.44 before 3.32.2.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2026-82747
Confirmed fixed CVEs
Not specified
Updated in this feed
3 Nov 2026, 14:13 UTC · Revision 1

Source evidence

Ash.Policy.Authorizer returns records denied by a runtime read policy to any actor

core-osv · Original source

Published 1 Sept 2026, 04:14 UTC

Incorrect Authorization vulnerability in ash-project ash returns records that a runtime read policy denies to any actor. When a resource has an access_type :runtime read policy (a check evaluated per record rather than compiled to a filter), Ash.Policy.Authorizer decides each record in check_result/1 (lib/ash/policy/authorizer/authorizer.ex) by discarding impossible policy scenarios and inspecting what remains. When every scenario for a record was impossible, meaning no policy can authorize it and it must be forbidden, the empty-scenario branch instead kept the record ({[record | data], authorizer, any_forbidden?}) and returned it as authorized. As a result, records the runtime read policy denies are returned to any actor. The fix forbids a record whose scenarios are all impossible. This issue affects ash: from 3.4.44 before 3.32.2.

osv:CVE-2026-82747
Complete source record
{
  "id": "87aaa95cd96024a61ee018491ab1bbc295ade65a1b95fae820b485b8800569d0",
  "url": "https://osv.dev/vulnerability/CVE-2026-82747",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Ash.Policy.Authorizer returns records denied by a runtime read policy to any actor",
    "summary": "Incorrect Authorization vulnerability in ash-project ash returns records that a runtime read policy denies to any actor. When a resource has an access_type :runtime read policy (a check evaluated per record rather than compiled to a filter), Ash.Policy.Authorizer decides each record in check_result/1 (lib/ash/policy/authorizer/authorizer.ex) by discarding impossible policy scenarios and inspecting what remains. When every scenario for a record was impossible, meaning no policy can authorize it and it must be forbidden, the empty-scenario branch instead kept the record ({[record | data], authorizer, any_forbidden?}) and returned it as authorized. As a result, records the runtime read policy denies are returned to any actor. The fix forbids a record whose scenarios are all impossible. This issue affects ash: from 3.4.44 before 3.32.2.",
    "evidence": "osv:CVE-2026-82747",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-82747",
      "aliases": [
        "CVE-2026-82747",
        "EEF-CVE-2026-82747",
        "GHSA-4259-gvr2-4xhq"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/ash-project/ash",
              "type": "GIT",
              "events": [
                {
                  "introduced": "f4a8ff53fd3b974468d73685cd3fc842ef893de3"
                },
                {
                  "fixed": "6eddb8ab26e45023faf0c79ebd152bb40aefda02"
                },
                {
                  "introduced": "8526e6e95befddc0b5797589fcc8bb50ce262c9a"
                },
                {
                  "fixed": "c4505a40d1f28ddb6a82fa7c12955d511f01d479"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "f4a8ff53fd3b974468d73685cd3fc842ef893de3"
                      },
                      {
                        "fixed": "6eddb8ab26e45023faf0c79ebd152bb40aefda02"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "introduced": "3.4.44"
                      },
                      {
                        "fixed": "3.32.2"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "fixed": "6eddb8ab26e45023faf0c79ebd152bb40aefda02"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v3.32.1",
            "v3.31.3",
            "v3.31.2",
            "v3.31.1",
            "v3.31.0",
            "v3.30.1",
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            "v3.6.0",
            "v3.5.43",
            "v3.5.42",
            "v3.5.41",
            "v3.5.39",
            "v3.5.38",
            "v3.5.37",
            "v3.5.36",
            "v3.5.35",
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          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-82747.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:29.360759220Z",
      "provider": "osv",
      "references": [
        "https://cna.erlef.org/cves/CVE-2026-82747.html",
        "https://github.com",
        "https://osv.dev/vulnerability/EEF-CVE-2026-82747",
        "https://repo.hex.pm",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/82xxx/CVE-2026-82747.json",
        "https://github.com/ash-project/ash/security/advisories/GHSA-4259-gvr2-4xhq",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-82747",
        "https://github.com/ash-project/ash/commit/6eddb8ab26e45023faf0c79ebd152bb40aefda02",
        "https://github.com/ash-project/ash"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-863"
        ],
        "cna_assigner": "EEF",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/82xxx/CVE-2026-82747.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-82747",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 496269,
  "published_at": "2026-09-01T04:14:57.84+00:00"
}